1. Field of the Invention
This invention relates to a humidifier for supplying moisture to increase the humidity of the air in a room or the like.
2. Description of the Prior Art
For energy saving, the recent living space has been improved in heat insulation and in air tightness, and there has been a strong demand for air-conditioning such living spaces to a higher degree. An air-conditioning operation includes temperature control, humidity control, and harmful air component control. For the temperature control, a variety of heating or cooling systems satisfactory in performance have been put in practical use; however, for the humidity control and the harmful air component control, no acceptable means have been proposed yet.
As for humidity control, there are available a natural evaporation type humidifier, an electrically heating type humidifier, a water spray type humidifier, and an ultrasonic humidifier. However, the natural evaporation type humidifier is disadvantageous in that it is small in humidifying capacity. The electrically heating type humidifier is high in running cost. The water spray type humidifier is low in humidifying efficiency, and is unavoidably bulky. The ultrasonic humidifier suffers from difficulties that it is high in initial cost, and short in service life, and it is liable to scatter various bacteria and fine particles of calcium carbonate contained in the water.
In view of the foregoing, the present application has conducted intensive research on the natural evaporation type humidifier which is smaller in initial cost and in running cost than the others, and is higher in safety being less scattering various bacteria or fine particles of calcium carbonate, to increase the humidifying capacity in which it was disadvantageous.
It is essential for the natural evaporation type humidifier to have a large area for water evaporation. Therefore, one example of the natural evaporation type humidifier employs a vat-shaped container having a large opening, and another example is so designed that water is supplied to a board or cloth of a hydrophilic material so that it is brought into contact with the air by capillarity. In those humidifiers, water is brought directly into contact with air, and therefore various bacteria and fine particles of calcium carbonate contained in the water are scattered to some extent. In addition, those humidifiers are insufficient in humidifying capacity.
In order to eliminate the above-described difficulties, the applicant has conducted research on a method of increasing the water evaporating area in the humidifier, and proposed the following humidifier: As shown in FIG. 17, a humidifying tubular film structure 1 is made of a waterproof and moisture-permeable film 1, and, in order to allow water to smoothly flow into the tubular film structure 1 thus formed, a spacer 7 is inserted into the latter 1 in such a manner that flat chambers several milli-meters in height are formed in it. The flat chambers are filled with water, and steam passed through the waterproof and moisture-permeable film 2 of the tubular film structure 1 is contained in the air supplied to the outer surface of the latter 1, to increase the humidity of the air. More specifically, a humidifier having a humidifier body 8 as shown in FIG. 18 has been proposed. The humidifier body 8 is formed as follows: That is, a corrugated spacer board 4 of synthetic resin or the like adapted to form spaces into which air is supplied is laid over the above-described tubular film structure 1, and the spacer board 4 and the tubular film structure 1 are spirally wound. In the humidifier, the water evaporating area is markedly increased, various bacteria and fine particles of calcium carbonate are scarcely scattered. Those facts have been disclosed by Unexamined Japanese Patent Applications (Kokai) Sho-60-171337/(1985), Sho-61-175421/ (1986), Sho-61-237942/(1986), and Sho-61-250429/(1986).
In the above-described conventional humidifier, as shown in FIG. 17 the humidifying tubular film structure 1 and the spacer 7 are formed separately. Hence, when water is supplied to the humidifier body 8 for humidification which has been formed by spirally winding the spacer board 4 and the tubular film structure 1 with the spacer 7, the humidifier suffers from the following difficulties: As shown in FIG. 19, the tubular film structure 1 is inflated by water pressure, so that it is partially brought into close contact with the spacer board 4 which is not gas-permeable, so that the air contact area of the waterproof and moisture-permeable film 2 is decreased as much; that is, the amount of humidification is decreased. Furthermore, the air passage area is decreased as much as the tubular film structure 1 is inflated, and the resistance against the air supplied to the humidifier body 8 is therefore increased. FIG. 20 is a graphical representation indicating water supply time, air resistance, and humidifying capacity with respect to water supply pressure in the humidifier. When, in order to prevent the inflation of the tubular film structure 1, the pressure of the water supplied to the latter 1 is decreased, the water supplying capacity for the tubular film structure 1 is decreased, as a result of which it becomes difficult to supply water to the whole tubular film structure, and the humidifying capacity is therefore decreased. That is, contradictorily, the prevention of the inflation of the tubular film structure results in the decrease of the humidifying capacity. Thus, there has been a strong demand for a drastic solution of the above-described problems.